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01 February 2013 Question by: Rapid Customer
Q. Hello,
I am still confused as to which parts I need to order to get the exact setup of the product shown in the image. Do I just need to order the Plastic Proximity Switch (78-2070) to get the reed switch and the magnet or do I need to order the side entry magnet as well (78-2092)?
Thanks,
Owen
A. Hi Owen. Thank you for your question. To get the set up in the image – both the magnet and switch are required as separate items. This is because any magnet will operate the switch – but the distance at which it will operate will vary depending on the magnets strength – by using the manufacturers own magnet – the distance has been measured to reflect the strength of the magnet they supply.
29 January 2013 Question by: Rapid Customer
Q. Hello,
I am confused as to the difference between magnet number: FM106MW Rear Entry, and: FM102MW Side Entry. What exactly is the difference between the magnets and which would be more appropriate for detecting an intruder on a shed door?
Thanks
Owen
A. Hi Owen. Thank you for your question. The difference is purely in the construction shape – the side entry is the product illustrated – back entry would have the wires coming from midway down the long side as viewed – ie from the back rather than the side. Other than that they are the same.
It is purely a matter of convenience for construction. For example the rear entry can be located at the top or bottom of the door and the wires go directly away from the door making it less likely they could be cut prior.
However if it were somehow recessed into the floor or top of the door jamb – side entry may be more convenient for positioning the cables.
29 December 2012 Question by: Rapid Customer
| Product code: 78-2070
Q. Hello,
I am having trouble understanding the concept of NO or NC.
I am looking for a proximity switch, that is open circuit when the magnet is close. Also, goes closed circuit when the magnet is absent. Will this product do this, or do you have a product that will?
Thanks.
A. Hi Geoff. Thank you for your question. You need a normally closed version from what you have said, something like the 78-1006 or 78-0780.
Normally Open (NO) and Normally Closed (NC) describe the state, or position, of contacts in a spring-loaded switch (forces other than springs can be used, but spring-loaded switches are by far the most common).
Switch contacts can be open or closed. Closed contacts can conduct current through the switch, while open contacts can not conduct current. A spring-loaded switch uses spring force to hold the contacts in one position or the other. The switch can have multiple sets of contacts, so some contacts can be NC, while others are NO on the same switch.
NC contacts will be closed when the spring is in its more relaxed (resting) position. The contacts will open only when something (a solenoid or some other mechanical force) causes the contacts to move from their resting position.
NO contacts work the other way. They are normally open when the spring is in its more relaxed position and close only when the switch is forced to its other position
The switch will always return to its resting position when the mechanical force is removed. Note that it is not true that the non-energized state is NO. The non-energized (resting) state can be either NC or NO, depending on the design of the switch. And as mentioned earlier, many switches come with one set of contacts NO and another set of contacts.
